Gas supply member, plasma treatment method, and method of forming yttria-containing film

ABSTRACT

According to one embodiment, a gas supply member is provided with a gas supply passage including a gas flow channel with a first diameter, and an exhaust port connected to one end portion of the gas flow channel and provided to a surface of a downstream side of the gas supply member. An yttria-containing film is formed on a surface constituting the exhaust port and the surface of the downstream side of the gas supply member. At least a part of the surface constituting the exhaust port is formed with a curved surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2010-180790, filed on Aug. 12,2010, and the prior Japanese Patent Application No. 2011-60711, filed onMar. 18, 2011; the entire contents of all of which are incorporatedherein by reference.

FIELD

Embodiments described herein relate generally to a gas supply member, aplasma treatment method, and a method of forming an yttria-containingfilm.

BACKGROUND

Conventionally, in a microfabrication process for manufacturing asemiconductor device, a liquid crystal display device and the like, areactive ion etching (RIE) apparatus is used. In the RIE apparatus, theinside of a chamber is first adjusted to enter a low pressure state,fluorine-based gas or chlorine-based gas is then introduced into thechamber to generate a plasma phase, and etching is performed. Since amember constituting the inner walls and inner portions of the RIEapparatus is susceptible to plasma and thus is likely to easily corrodewhen it is exposed to plasma, the member is usually coated with aprotective film made of a material having a high plasma resistance suchas yttria or alumina.

However, although the protective film such as yttria is coated onto themember constituting the inner walls and inner portions of the RIEapparatus, the protective film is still likely to degrade due toshedding of particles of the protective film, crack in the protectivefilm and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view schematically illustrating an example of theconfiguration of a plasma treatment apparatus according to a firstembodiment;

FIG. 2 is a partial sectional view schematically illustrating the shapein the vicinity of an exhaust port of a shower head according the firstembodiment;

FIG. 3A and FIG. 3B are sectional views schematically illustrating anexample of a protective film;

FIG. 4A and FIG. 4B are sectional views schematically illustrating anexample of the procedure of a method for forming a protective filmaccording to the first embodiment;

FIG. 5 is a sectional view schematically illustrating the shape in thevicinity of an exhaust port of a conventional shower head;

FIG. 6 is a sectional view schematically illustrating the shape in thevicinity of an exhaust port of a shower head according a secondembodiment;

FIG. 7 is a sectional view schematically illustrating the shape in thevicinity of an exhaust port of a shower head according a thirdembodiment;

FIG. 8 is a sectional view schematically illustrating the shape in thevicinity of an exhaust port of a shower head according a fourthembodiment;

FIG. 9A to FIG. 9F are sectional views schematically illustrating anexample of the procedure of a first method for forming a protective filmon a shower head according to the fourth embodiment; and

FIG. 10A to FIG. 10D are sectional views schematically illustrating anexample of the procedure of a second method for forming a protectivefilm on a shower head according to the fourth embodiment.

DETAILED DESCRIPTION

In general, according to one embodiment, a gas supply member includes agas supply passage having a gas flow channel with a first diameter, anexhaust port connected to one end portion of the gas flow channel andinstalled at the surface of a downstream side of the gas supply member.An yttria-containing film is provided on a surface constituting theexhaust port and the surface of the downstream side of the gas supplymember. Furthermore, at least a part of the surface constituting theexhaust port is formed with a curved surface.

A gas supply member, a plasma treatment method, and a method of formingan yttria-containing film according to the embodiments will be describedin detail below with reference to the accompanying drawings. The presentinvention is not limited to the following embodiments. Furthermore,sectional views of films used in the following embodiments areschematic, and relationship between the thickness and width of layersand the ratio of thicknesses of the layers differ from the actualrelationship or ratio.

(First Embodiment)

In a first embodiment, the case in which a film having resistanceagainst the exposure of plasma is applied to the inner wall of a plasmatreatment apparatus will be described as an example. FIG. 1 is asectional view schematically illustrating an example of theconfiguration of a plasma treatment apparatus according to the firstembodiment. Here, a RIE apparatus is used as a plasma treatmentapparatus 10. The plasma treatment apparatus 10 includes a chamber 11airtightly sealed and made of, for example, aluminum. The chamber 11 isgrounded.

The chamber 11 is provided therein with a substrate holding unit(support table) 21 that horizontally supports a substrate 100 which is aprocess target such as a wafer and serves as a lower electrode. Thesubstrate holding unit 21 is provided on the surface thereof with aholding mechanism such as an electrostatic chuck mechanism (not shown)that electrostatically attracts the substrate 100. An insulating ring 22is provided to cover the edges of lateral side and bottom side of thesubstrate holding unit 21, and a focus ring 23 is provided on the outerperiphery of the upper portion of the substrate holding unit 21 coveredby the insulating ring 22. The focus ring 23 is a member provided inorder to adjust an electric field such that the electric field is notbiased with respect to the vertical direction (direction vertical to asubstrate surface) at the edges of the substrate 100 when the substrate100 is etched.

Furthermore, the substrate holding unit 21 is supported on a supportsection 12 cylindrically protruding upright from the bottom wall nearthe center of the chamber 11 via the insulating ring 22 such that thesubstrate holding unit 21 is positioned near the center of the chamber11. A baffle plate 24 is provided between the insulating ring 22 and thesidewall of the chamber 11. The baffle plate 24 is formed with aplurality of gas discharge holes 25 passing through the plate in thethickness direction of the plate. Furthermore, a power feed line 31 forsupplying radio frequency power is connected to the substrate holdingunit 21, and a blocking condenser 32, a matching device 33, and a radiofrequency power supply 34 are connected to the power feed line 31. Radiofrequency power with a predetermined frequency is supplied from theradio frequency power supply 34 to the substrate holding unit 21.

A shower head 41 serving as an upper electrode is provided above thesubstrate holding unit 21 to face the substrate holding unit 21 servingas the lower electrode. The shower head 41 is fixed to the sidewall nearthe upper portion of the chamber 11 while being spaced apart from thesubstrate holding unit 21 by a predetermined distance, thereby facingthe substrate holding unit 21 in parallel to the substrate holding unit21. With such a structure, the shower head 41 and the substrate holdingunit 21 form a pair of parallel flat plate electrodes. Furthermore, theshower head 41 is formed with a plurality of gas supply passages 42passing through the plate in the thickness direction of the plate.

A gas supply port 13 is provided near the upper portion of the chamber11 to supply treatment gas used in plasma treatment, and a gas supplyapparatus (not shown) is connected to the gas supply port 13 through apipe.

A gas exhaust port 14 is provided at a lower portion of the chamber 11below the substrate holding unit 21 and the baffle plate 24, and avacuum pump (not shown) is connected to the gas exhaust port 14 througha pipe.

As described above, an area of the chamber 11 partitioned by thesubstrate holding unit 21, the baffle plate 24, and the shower head 41is a plasma treatment chamber 61, an upper area of the chamber 11partitioned by the shower head 41 is a gas supply chamber 62, and alower area of the chamber 11 partitioned by the substrate holding unit21 and the baffle plate 24 is a gas exhaust chamber 63.

A protective film 50 is formed on the surface of a member constitutingthe plasma treatment apparatus 10 with such a configuration, which is incontact with a plasma generation area, that is, on the surface of amember constituting the plasma treatment chamber 61. In detail, theprotective film 50 including an yttria-containing film (hereinafter,referred to as an yttria film) is formed on the inner wall surface ofthe chamber 11 which constitutes the plasma treatment chamber 61, thesurface of the shower head 41 facing the plasma treatment chamber 61,the surface of the baffle plate 24 facing the plasma treatment chamber61, the surface of the focus ring 23, and the surface of the substrateholding unit 21 onto which the substrate 100 is loaded.

The overview of processes performed by the plasma treatment apparatus 10configured as above will be described below. First, the substrate 100which is a process target is loaded onto the substrate holding unit 21,and the substrate 100 is fixed by the electrostatic chuck mechanism, forexample. Next, the inside of the chamber 11 is vacuum-sucked by thevacuum pump (not shown) connected to the gas exhaust port 14. At thistime, since the gas exhaust chamber 63 and the plasma treatment chamber61 are connected to each other through gas discharge holes 25 formedthrough the baffle plate 24, and the plasma treatment chamber 61 and thegas supply chamber 62 are connected to each other through the gas supplypassages 42 of the shower head 41, the entire inside space of thechamber 11 is vacuum-sucked through the vacuum pump connected to the gasexhaust port 14.

Then, when the chamber 11 reaches a predetermined pressure, thetreatment gas is supplied from the gas supply apparatus (not shown) tothe gas supply chamber 62, and is supplied to the plasma treatmentchamber 61 through the gas supply passages 42 of the shower head 41.When pressure in the plasma treatment chamber 61 reaches a predeterminedpressure, a radio frequency voltage is applied to the substrate holdingunit 21 (the lower electrode) in the state in which the shower head 41(the upper electrode) is grounded, so that plasma is generated in theplasma treatment chamber 61. Here, since the radio frequency voltage isapplied to the lower electrode, potential gradient occurs between theplasma and the substrate 100, so that ions in plasma state areaccelerated toward the substrate holding unit 21 and thus an etchingprocess is performed.

FIG. 2 is a partial sectional view schematically illustrating the shapein the vicinity of the exhaust port of the shower head according to thefirst embodiment. The shower head 41 serving as the gas supply member isprovided with the gas supply passages 42. The gas supply passages 42,for example, pass through a member constituting the shower head 41toward the bottom surface (a surface of a downstream side of gas flow)from the top surface of the shower head 41 as illustrated in FIG. 1. Thegas supply passage 42 includes a gas flow channel 421 with the firstdiameter, and an exhaust port 422 with an opening diameter increasing ina tilted manner from one end portion of the gas flow channel 421 so asto be the second diameter which is larger than the first diameter. In anexample, the shower head 41 is processed to have a tapered shape inwhich the diameter of the opening of the shower head 41 increases in thevicinity of the exhaust port 422 of the gas supply passage 42. As themember constituting the shower head 41, for example, aluminum and thelike can be used.

In the shower head 41 as described above, the protective film 50 isprovided on the formation surface of the exhaust port 422 and in thevicinity of a inflectional section 43 of the surface of the downstreamside, which is one main surface of the shower head 41, such that atleast a part of the inflectional section 43 is exposed. Here, when afilm formation target includes a plurality of surfaces (planes or curvedsurfaces) which are not parallel to one another, the inflectionalsection 43 indicates a protruded section formed by bonding one surfaceserving as a reference to another surface at an angle of more than 90°.Furthermore, in this example, a lateral side of the protective film 50formed in the vicinity of the inflectional section 43 positioned at theboundary between the gas flow channel 421 and the exhaust port 422 isapproximately level with (is flush with) the inner surface of the gasflow channel 421. That is, a ring structure formed by the protectivefilm 50 formed in the vicinity of the inflectional section 43 at theupper portion of the exhaust port 422 has a diameter which isapproximately the same as the first diameter. As the protective film 50,an yttria film having a thickness of 50 μm to 100 μmay be used.

FIG. 3A and FIG. 3B are sectional views schematically illustrating anexample of the protective film. As the protective film 50, a generalyttria film 51 formed on a constituting member 55 (a film formationtarget) as illustrated in FIG. 3A may be used. The protective film 50may include a melt-solidified part (a melt-solidified film) 53 obtainedby melting the yttria film 51 of FIG. 3A from the surface in the rangeof the thickness of the yttria film 51 as illustrated in FIG. 3B. Insuch a case, the yttria film having the total thickness may be used asthe melt solidified part 53, or the protective film 50 may have astacked structure of the melt solidified part 53 obtained by melting theyttria film 51 from the surface in the range of a predeterminedthickness and a non-melt solidified part (a non-melt solidified film)52. The melt solidified part 53 has a restricted inter-particle gap ascompared with the non-melt solidified part 52, is high density, and hasa planarized surface. The melt solidified part 53 has a density greaterthan that of the non-melt solidified part 52. Preferably, the non-meltsolidified part 52 has a density range of 2.0 g/cm³ to 4.0 g/cm³, andthe melt solidified part 53 has a density range of 4.0 g/cm³ to 5.0g/cm³.

So far, the case in which the protective film 50 including the yttriafilm is formed on the shower head 41 made of aluminum has beendescribed. However, an alumina film may be formed on aluminum, and theprotective film 50 may be further formed on the alumina film.

Next, a method of forming the protective film 50 on the shower head 41will be described. FIG. 4A and FIG. 4B are sectional views schematicallyillustrating an example of the procedure of the method of forming theprotective film according to the first embodiment. First, as illustratedin FIG. 4A, for example, the protective film 50 including the yttriafilm and having a thickness of 50 μm to 100 μm is formed on the surface(the surface of the side of the exhaust port 422) of the downstream sideof the shower head 41 made of aluminum and formed with the gas supplypassage 42, and on the inner surface over a part of the gas flow channel421 from the exhaust port 422. That is, the protective film 50 is formedto cover the inflectional section 43 at which the diameter of the gassupply passage 42 changes. In order to form the yttria film constitutingthe protective film 50, a spraying method, a chemical vapor deposition(CVD) method, an aerosol deposition method, a cold spraying method, agas deposition method, an electrostatic powder impact deposition method,an impact sintering method and the like can be used.

Next, as illustrated in FIG. 4B, the protective film 50 formed on theinner surface of the gas flow channel 421, for example, is removed usingpolishing and the like. In this way, only one surface (the lowersurface), which constitutes the inflectional section 43, of the showerhead 41 is coated, and the lateral side of the protective film 50 formedin the vicinity of the inflectional section 43 positioned at the innersurface of the exhaust port 422 is approximately level with the innersurface of the gas flow channel 421. Consequently, the shower head 41with the structure illustrated in FIG. 2 is achieved.

In addition, in the formation of the protective film 50 illustrated inFIG. 4A, after the yttria film is formed using a spraying method, a CVDmethod, an aerosol deposition method, a cold spraying method, a gasdeposition method, an electrostatic powder impact deposition method, animpact sintering method and the like, the yttria film may be subject tosurface treatment, melted in the range of the thickness of a film formedfrom the surface of the yttria film, and then solidified. As the surfacetreatment, for example, it is possible to use a method capable ofselectively thermally fusing the surface of the yttria film, such aslaser annealing treatment or plasma jet treatment.

Hereafter, the effects of the first embodiment will be described bycomparing the first embodiment with a comparison example. FIG. 5 is asectional view schematically illustrating the shape in the vicinity ofan exhaust port of a conventional shower head. A shower head 41 servingas a gas supply member, for example, is provided with a gas supplypassage 42 which is configured to pass through a member constituting theshower head 41 toward the surface of a downstream side from the uppersurface of the shower head 41. The gas supply passage 42 includes a gasflow channel 421 with a first diameter, and an exhaust port 422 with anopening diameter increasing from one end portion of the gas flow channel421 so as to be a second diameter which is larger than the firstdiameter. In the example of FIG. 5, a protective film 50 is provided onthe surface of the downstream side of the shower head 41, the innersurface of the exhaust port 422, and in the vicinity of the gas flowchannel 421 adjacent to the exhaust port 422. That is, the protectivefilm 50 is provided to cover a inflectional section 43 of the gas supplypassage 42.

In general, since aluminum has a linear expansion coefficient of about24×10⁻⁶/° C. and yttria has a linear expansion coefficient of about7×10⁻⁶/° C., a large difference exists between the two linear expansioncoefficients. Therefore, when thermal expansion occurs due to heatingduring plasma treatment 70, a crack 56 may easily occur in theprotective film 50. Specifically, the crack 56 and the like may easilyoccur in the inflectional section 43 due to the thermal expansiondifference between yttria and aluminum during the heating (during theplasma treatment 70).

Meanwhile, in the first embodiment, as illustrated in FIG. 2, theprotective film 50 does not extend over the inflectional section 43 ofthe shower head 41. In a detailed structure example, an inner surface asa part of the gas supply passage 42 formed by the protective film 50formed in the vicinity of the inflectional section 43 of the exhaustport 422 is approximately level with the inner surface of the gas flowchannel 421. In this way, even if thermal expansion difference occursbetween the shower head 41 and the protective film 50 due to heatingduring the plasma treatment, crack does not easily occur in theprotective film 50 in the vicinity of the inflectional section 43.

(Second Embodiment)

FIG. 6 is a sectional view schematically illustrating the shape in thevicinity of an exhaust port of a shower head according to a secondembodiment. The second embodiment is different from the first embodimentin that an exhaust port 422 of a gas flow channel 421 of a shower head41 serving as a base material includes a plurality of surfaces withangles different from each other. Even in the second embodiment, aprotective film 50 is formed in the vicinity of the exhaust port 422 andon the surface of the downstream side of the shower head 41 serving asthe gas supply member. In the protective film 50 with such a structure,stress concentrated on a corner section 44 is attenuated. In the secondembodiment, when a film thickness d₂ of the corner section 44 existingin an area coated with the protective film 50 is thicker than a filmthickness d₁ of another portion, crack does not easily occur becausestress is further attenuated. Here, the film thicknesses d₁ and d₂ arethe thicknesses of the protective film 50 in the normal direction ateach position of the shower head 41. In detail, preferably, the filmthickness d₁ at a portion other than the corner section 44 is about 10μm to about 100 μm, and the film thickness d₂ in the vicinity of thecorner section 44 is thicker than the film thickness d₁ by about one totwo times, that is, about 10 μm to about 200 μm.

In addition, as illustrated in this figure, a cross angle of the cornersection 44 formed in the exhaust port 422 of the shower head 41 may belarge as compared with the case of FIG. 2. Moreover, the protective film50 can be formed on the above-described shower head 41 using a methodthe same as that of the first embodiment.

(Third Embodiment)

FIG. 7 is a sectional view schematically illustrating a thirdembodiment. In the second embodiment illustrated in FIG. 6, the surfaceforming the exhaust port 422 of the shower head 41 serving as a basematerial and the surface (the lower surface) of the downstream side ofgas flow are not curved surfaces, and the respective surfaces areconnected at a predetermined angle to form the corner section 44.However, in the third embodiment illustrated in FIG. 7, the surfaceforming a gas flow channel 421 of a shower head 41 serving as a basematerial and a surface 41A of a downstream side of the shower head 41are connected to each other by a smooth curved surface. Here, the curvedsurface of an exhaust port 422 is formed to have a tapered shape suchthat the opening diameter of the exhaust port 422 increases as it goesfar from a connection part with the gas flow channel 421, and theopening diameter at the surface 41A of the downstream side of the showerhead 41 is the second diameter which is larger than a first diameter. Inthe example of FIG. 7, all surfaces constituting the exhaust port 422are formed by curved surfaces. However, the embodiment is not limitedthereto. For example, preferably, a curved surface may be formed near(an area corresponding to the corner section 44 of FIG. 6) at least aconnection part of the surfaces constituting the exhaust port 422 andthe surface 41A of the downstream side of the shower head 41. Inaddition, when gas exhausted from the exhaust port 422 generates aplasma phase, the surface 41A of the downstream side of the shower head41 is a surface constituting the shower head 41 facing an area whereplasma is generated. Furthermore, preferably, the curvature radius ofthe curved surface forming the exhaust port 422 of the shower head 41illustrated in FIG. 7 is about 100 μm to about 500 μm.

The thickness of a protective film 50 formed on the surface forming theexhaust port 422 of the shower head 41 is approximately constant.Furthermore, the protective film 50 is also formed on the surfacesforming the exhaust port 422 and in the vicinity of the surfaces formingthe gas flow channel 421, which are adjacent to the exhaust port 422.Moreover, since the formation surface of the exhaust port 422 of theshower head 41 serving as a base is a curved surface, the protectivefilm 50 is configured to have a curved surface shape according to theformation surface thereof.

In addition, since others are the same as the first embodiment,description thereof will not be repeated. For example, the protectivefilm 50 used is the same as the protective film 50 used in the firstembodiment. Furthermore, the protective film 50 may be directly formedon the shower head 41 made of aluminum, or an alumina film may be formedon aluminum and the protective film 50 may be formed on the aluminafilm. In addition, an yttria film constituting the protective film 50can also be formed using the method described in the first embodiment.

According to the third embodiment, since the exhaust port 422 of theshower head 41 serving as the base is formed with the curved surface andthe protective film 50 is formed on the curved surface, stressconcentrating on the corner section 44 is further reduced as comparedwith the second embodiment, so that crack does not easily occur ascompared with the second embodiment.

(Fourth Embodiment)

FIG. 8 is a sectional view schematically illustrating the shape in thevicinity of an exhaust port of a shower head according a fourthembodiment. The fourth embodiment has a structure approximately the sameas that of the third embodiment. That is, in the third embodiment, thethickness of the protective film 50 on the exhaust port 422 isapproximately constant. However, in the fourth embodiment, the thicknessof a protective film 50 is gradually reduced toward the vicinity of thecenter of an exhaust port 422. Furthermore, the fourth embodiment isdifferent from the third embodiment in that the yttria film is notformed in the side of a gas flow channel 421. In the protective film 50with such a structure, since stress concentrated on a corner section 44is further reduced as compared with the second embodiment, crack doesnot easily occur as compared with the second embodiment. Preferably, thefilm thickness of a curved part continuously changes from about 10 μm toabout 100 μm. Preferably, the curvature radius of the curved surface ofa shower head 41 illustrated in FIG. 8 is about 100 μm to about 500 μmsimilarly to FIG. 7.

In addition, similarly to the third embodiment, the curved surface ofthe exhaust port 422 is formed to have a tapered shape such that theopening diameter of the exhaust port 422 increases as it goes far from aconnection part with the gas flow channel 421, and the opening diameterat a surface 41A of the downstream side of the shower head 41 is asecond diameter which is larger than a first diameter. In the example ofFIG. 8, all surfaces constituting the exhaust port 422 are formed bycurved surfaces. However, the embodiment is not limited thereto. Forexample, preferably, a curved surface may be formed near (an areacorresponding to the corner section 44 of FIG. 6) at least a connectionpart of the surfaces constituting the exhaust port 422 and the surface41A of the downstream side of the shower head 41. In addition, when gasexhausted from the exhaust port 422 generates a plasma phase, thesurface 41A of the downstream side of the shower head 41 is a surfaceconstituting the shower head 41 facing an area where plasma isgenerated.

Next, a method for forming the protective film 50 on the shower headaccording to the fourth embodiment will be described. FIG. 9A to FIG. 9Fare a series of sectional views schematically illustrating a firstmethod of forming the protective film in the vicinity of the exhaustport of the shower head illustrated in FIG. 8 according to the fourthembodiment. In the fourth embodiment, the shower head 41 includes thegas flow channel 421 with a first diameter, and the exhaust port 422with the second diameter at the surface of a downstream side which is aplane while an opening diameter expands from the lower end of the gasflow channel 421 along a smooth surface. The protective film 50 isformed such that the film thickness thereof gradually increases towardthe surface of the downstream side of the shower head 41 from theinflectional section 43 positioned at the boundary between the gas flowchannel 421 on the formation surface of the exhaust port 422, and theexhaust port 422. Furthermore, the protective film 50 has anapproximately uniform thickness on the surface of the downstream side ofthe shower head 41. Even in such a structure, the protective film 50 isnot formed on the gas flow channel 421, and a lateral side of theprotective film 50 formed in the vicinity of the inflectional section 43positioned at the boundary between the gas flow channel 421 and theexhaust port 422 is approximately level with the inner surface of thegas flow channel 421.

FIG. 9A to FIG. 9F are sectional views schematically illustrating anexample of the procedure of the first method of forming the protectivefilm on the shower head according to the fourth embodiment. Hereafter,the description will be made by illustrating only a part of the gassupply passage 42 of the shower head 41. First, as illustrated in FIG.9A, for example, the gas supply passage 42 is formed in a base materialmade of aluminum. As described above, the gas supply passage 42 includesthe gas flow channel 421 with the first diameter, and the exhaust port422 with the second diameter at the surface of the downstream side whichis the plane while the opening diameter expands from the lower end ofthe gas flow channel 421 along the smooth surface, thereby forming theshower head 41.

Next, as illustrated in FIG. 9B, negative-type photoresist 101 is coatedfrom the side of the exhaust port 422 of the shower head 41. Then, asillustrated in FIG. 9C, the negative-type photoresist 101 is exposedfrom the upper surface (the formation surface of the gas flow channel421) of the shower head 41 using ultraviolet and the like, so that onlyan exposed part of the negative-type photoresist 101 is cured, resultingin the generation of a sacrificial layer 101 a which is a plug member.At this time, only a part of the gas flow channel 421 of the shower head41 is exposed, so that negative-type photoresist 101 formed in an area(which is not the gas flow channel 421) of the surface of the downstreamside of the shower head 41 is not cured because the ultraviolet isblocked by the member of the shower head 41, for example. Thereafter, asillustrated in FIG. 9D, a development process is performed to remove theuncured negative-type photoresist 101. In this way, the sacrificiallayer 101 a remains in the gas flow channel 421. In addition, the lowerend portion of the sacrificial layer 101 a protrudes further toward thesurface of the downstream side of the shower head 41 than the boundarybetween the gas flow channel 421 and the exhaust port 422.

Next, as illustrated in FIG. 9E, the protective film 50 including theyttria film is formed on the formation surface (the surface of thedownstream side) of the exhaust port 422 of the shower head 41 providedwith the sacrificial layer 101 a. In order to form the yttria filmconstituting the protective film 50, it is possible to use a sprayingmethod, a CVD method, an aerosol deposition method, a cold sprayingmethod, a gas deposition method, an electrostatic powder impactdeposition method, an impact sintering method and the like. Here, theprotective film 50 having a thickness of 50 μm to 100 μm is formed onthe surface of the downstream side of the shower head 41. However, thethickness of the protective film 50 is gradually reduced toward thevicinity 105 of the center of the exhaust port 422 because yttriaparticles do not easily reach the vicinity 105 of the center.Furthermore, the protective film 50 is also formed in the vicinity ofthe upper surface of the sacrificial layer 101 a.

Next, as illustrated in FIG. 9F, the sacrificial layer 101 a is removedusing a method such as a resist stripping technique. In this way, theprotective film 50 is formed on both the surfaces constituting theexhaust port 422 of the shower head 41 and the surface of the downstreamside of the shower head 41.

The first formation method described above can also be applied to thefirst to third embodiments.

Furthermore, in order to form the protective film 50 on the shower head41 as illustrated in FIG. 8, a method other than the first formationmethod can also be used. Hereafter, a case for processing the vicinityof the exhaust port 422 of the shower head 41 illustrated in FIG. 8according to the fourth embodiment by using a method different from thefirst formation method will be described.

FIG. 10A to FIG. 10D are sectional views schematically illustrating anexample of the procedure of a second method of forming the protectivefilm on the shower head illustrated in FIG. 8 according to the fourthembodiment. Hereafter, the description will be made by illustrating onlya part of the gas supply passage 42 of the shower head 41. First, asillustrated in FIG. 10A, for example, the gas supply passage 42 isformed in a base material made of aluminum. As described above, the gassupply passage 42 includes the gas flow channel 421 with the firstdiameter, and the exhaust port 422 with the second diameter at thesurface of the downstream side which is the plane while the openingdiameter expands from the lower end of the gas flow channel 421 alongthe smooth surface, thereby forming the shower head 41.

Next, as illustrated in FIG. 10B, a tool 111 serving as a plug member isinserted into the gas flow channel 421. The tool 111 has a diameterapproximately the same as the first diameter of the gas flow channel421. The tool 111 is inserted to slightly protrude toward the exhaustport 422 from the surface (the formation side of the exhaust port 422)of the downstream side of the shower head 41. At this time, the gas flowchannel 421 of the shower head 41 is closed by the tool 111, and thelower end portion of the tool 111 is fixed to slightly protrude furthertoward the surface (the side where the opening diameter of the exhaustport 422 is expanded) of the downstream side than the boundary betweenthe gas flow channel 421 and the exhaust port 422.

Then, as illustrated in FIG. 10C, the protective film 50 including theyttria film is formed on the formation surface (the surface of thedownstream side) of the exhaust port 422 of the shower head 41 includingthe tool 111 inserted thereto. In order to form the yttria filmconstituting the protective film 50, it is possible to use a sprayingmethod, a CVD method, an aerosol deposition method, a cold sprayingmethod, a gas deposition method, an electrostatic powder impactdeposition method, an impact sintering method and the like. Here, theprotective film 50 having a thickness of 50 μm to 100 μm is formed onthe surface of the downstream side of the shower head 41. However, thethickness of the protective film 50 is gradually reduced toward thevicinity of the center of the exhaust port 422 because yttria particlesdo not easily reach the vicinity. Furthermore, since the gas flowchannel 421 is closed by the tool 111, the protective film 50 is notformed in the gas flow channel 421, but formed in the vicinity of theupper surface of the tool 111.

Thereafter, as illustrated in FIG. 10D, the tool 111 is removed. Here,the tool 111 is removed from the surface of the downstream side of theshower head 41 such that the protective film 50 is not damaged. In thisway, the protective film 50 is formed on both the surfaces constitutingthe exhaust port 422 of the shower head 41 and the surface of thedownstream side of the shower head 41.

In the second formation method, after the gas flow channel 421 is closedby the tool 111, since the protective film 50 is formed on both thesurface of the downstream side of the shower head 41 and the formationsurface of the exhaust port 422, and then the tool 111 is pulled outfrom the gas flow channel 421, it is possible to easily form theprotective film 50, as compared with the first formation method.Furthermore, since the tool 111 can be repeatedly used a plurality oftimes, it is possible to form the protective film 50 at a low cost, ascompared with the case of using resist in the first formation method.

In addition, in the first and second formation methods, the case, inwhich a lateral side as a part of the gas supply passage 42 formed bythe protective film 50 in the vicinity of the inflectional section 43positioned at the boundary between the gas flow channel 421 and theexhaust port 422 is level with the inner surface of the gas flow channel421 constituting the shower head 41, has been described with referenceto the figures. However, the embodiment is not limited thereto. Asdescribed above, the protective film 50 may be formed such that at leasta part of the inflectional section 43 is exposed.

In the fourth embodiment, at the time of plasma treatment, stressconcentration is reduced in the vicinity of the inflectional section 43and the corner section 44 where stress may be easily concentrated due tothe difference of linear expansion coefficients between the shower head41 and the protective film 50, and the occurrence of defect such ascrack is prevented. As a consequence, it is possible to prevent dustincluding yttria from being generated from the protective film 50.Furthermore, since additional processing such as polishing described inthe first embodiment is not necessary, the manufacturing cost isreduced, crack of the protective film 50, which may occur at the time ofpolishing, and dusting, which occurs at the time of polishing, are notproblematic.

Furthermore, in the first to fourth embodiments, the protective film 50formed on the shower head 41 of the RIE apparatus has been described asan example. However, the embodiments are not limited thereto. Forexample, it is possible to form the protective film 50 according to thefirst to fourth embodiments on members, other than the shower head 41,such as the inner wall of the chamber 11, the baffle plate 24, the focusring 23, the substrate holding unit 21 for holding a plasma treatmenttarget, and the like.

In addition, in the above description, the RIE apparatus has beendescribed as an example of the plasma treatment apparatus 10. However,it is possible to apply the above-described embodiments to allprocessing apparatuses such as a resist stripping apparatus, a chemicaldry etching (CDE) apparatus or a CVD apparatus, and all semiconductormanufacturing apparatuses.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A gas supply member forming an electrode in achamber, the gas supply member comprising: an electrode constitutingmember provided with a gas supply passage, the gas supply passageincluding a gas flow channel and an exhaust port, the exhaust port beingconnected to a first connection part which is one end portion of the gasflow channel and being provided to a downstream side of the electrodeconstituting member, the electrode constituting member having a firstflat surface at the downstream side; and an yttria-containing filmcoating a part of the electrode constituting member, wherein at least apart of a surface constituting the exhaust port of the electrodeconstituting member is formed with a curved surface, the surfaceconstituting the exhaust port and the first flat surface at thedownstream side of the electrode constituting member are connected toeach other by a smooth curved surface continuously, a diameter of theexhaust port increases as it goes far from the first connection partwith the gas flow channel, a diameter of the gas flow channel isentirely constant from the one end portion connected to the exhaustportion to the other end portion intersecting with a second flat surfaceat an upstream side of the electrode constituting member, the secondflat surface being parallel with the first flat surface, and theyttria-containing film is formed on the surface constituting the exhaustport and on the first flat surface at the downstream side of theelectrode constituting member and is not formed on an upstream side ofthe first connection part, the yttria-containing film having a curvedsurface.
 2. The gas supply member according to claim 1, wherein thecurved surface is formed near a second connection part between thesurface constituting the exhaust port and the first flat surface of thedownstream side of the electrode constituting member.
 3. The gas supplymember according to claim 1, wherein a thickness of theyttria-containing film decreases toward the first connection part. 4.The gas supply member according to claim 1, wherein the gas flow channelhas a first diameter, and an opening diameter at the first flat surfaceof the downstream side of the electrode constituting member is a seconddiameter which is larger than the first diameter.
 5. The gas supplymember according to claim 1, wherein, when a gas exhausted from theexhaust port and changed in the plasma state, the first flat surface ofthe downstream side of the electrode constituting member faces the gasin the plasma state.
 6. The gas supply member according to claim 1,wherein an alumina film is formed on the electrode constituting member,and the yttria-containing film is formed on the alumina film.
 7. The gassupply member according to claim 1, wherein the yttria-containing filmhas a melt-solidified part obtained by melting and solidifying theyttria-containing film from the surface in a range of a thickness of theyttria-containing film.
 8. The gas supply member according to claim 1,wherein the first flat surface at the downstream side of the electrodeconstituting member is parallel to a surface of a processing target tobe set in the chamber, the surface of processing target being set toface the electrode constituting member in the chamber.
 9. The gas supplymember according to claim 1, wherein a thickness at an end portion of anupstream side of the yttria-containing film gradually decreases towardthe first connection part.
 10. The gas supply member according to claim1, wherein the gas flow channel has a first diameter, the exhaust porthas a smooth curved surface between the first connection part and thefirst flat surface at the downstream side of the electrode constitutingmember, and a thickness of the yttria-containing film on the exhaustport decreases toward the first connection part.
 11. The gas supplymember according to claim 1, wherein, in a longitudinal section of thegas supply passage, the first connection part is a boundary between asmooth curved portion of the exhaust port and a linear portion of thegas flow channel.
 12. The gas supply member according to claim 11,wherein the yttria-containing film does not have a linear surface in thegas supply passage.
 13. The gas supply member according to claim 1,wherein the electrode constituting member is made of aluminum.
 14. Thegas supply member according to claim 1, wherein the curved surface isformed near a second connection part between the surface constitutingthe exhaust port and the first flat surface at the downstream side ofthe electrode constituting member.
 15. The gas supply member accordingto claim 13, wherein a thickness of the yttria-containing film decreasestoward the first connection part.